Reconditioning metal mold



June 18, 1929 vs-l. M. MARTIN ET AL RECONDITIONING METAL MOLDS Filed Sept. 27, 1926 2 Sheets-Sheet l wmv Qou R., QM. m bh.

`une 18, 1929.

lw. M. MARTIN 'ET AL REGONDITIONING METAL MOLDS Filed sept. 27, 192s l 2 sheets-sheet 2 NaN.

Patenten/lY (18, 1929..

UNITED lSTATES* PATENT oFFicE..

WILLIAM H. MARTIN AND enAnLEs N. enuncia, or BunLINGTo'N, NEW JERSEY.

y nEc'JoNl-JITIONIN;L METAL nenn. ef

lApplication med september 27, 192s. serial No. 137,965.

This'y invention relates to molding and has 'special'reference tol a method and apparatus for repairing cracked or ,checked metallic molds.

In themolding' of pipe and other like arti- -ject in use toalternate heating and cooling and Ythis sets up internal stresses which cause cracking' or checking of the internal surface ofthe mold sothat the article cast therein presents a rough exterior-and is dilicult and sometimes impossible to Withdraw from the mold. This is due partly to the development of the cracks themselves Aand partly to the .edges of the cracks curling upwards from the` lnormal surface of the mold. Consequently such metallic molds-have heretofore been disl carded as soon as such cracking or checking Abecameserious whilethe'mold actually, if the cracks were closed, could be used for a much longer time.

The present invention has for'its objects, among others, the provision of an improved method of,treating cracked metal molds to close the cracks and also the provision of improved apparatus whereby the method may be carried'in practical operation and wherein means will be provided for adjusting the device to suit molds of different internal diameters and molds having internaldiameters varying at different points such as tapered molds. Y f

` In the following detailed description of -this invention, we shall refer to the accom` panying drawin s in which:-

.F gure 1 is a ongitudinal section, partly in elevation, showing an improved device for closin the cracks in a mold of the character descri ed; c

Figure 2 is a section on the line 2-2 of Figure 1; v

Figure 3 is a diagrammatic section of a checked or cracked mold showing the characteristic condition of such mold before repairing; l

. Figure 4 is a view similar to Figure 3 showing diagrammati'cally a characteristic section through the mold after being repaired by the present method; 1 4

Figure 5 is a sectional view, partly in elevation, of an appiratus for treating molds in accordance wit vthis invention;4 l

\ Figures 6 and are diagrammatic sectional I views similar to Figs.` 3 and 4 showing respectively a checked and a repaired mold when the checks are not very large.

In carrying out this method by whic cracked or checked molds are repaired, the

mold is suitably supported and the edges of the cracks are forced down to thenormal surface of the mold. This causes the up-y curved edges on the opposite sides of the crack to move toward each other until they contact and thus close the crack. The neces"- y and smooth the surface of the mold by forcing the material at the opposite edges of each crack together and into conformity with the .i

normal surface of. the mold.-

Any suitable apparatus for supporting the mold and for causing relative movement between the mold andthe operating mechanism maybe employed. Hence for purposes of illustration only, We have shown in` Fig: 5, a mold supporting arrangement comprising a casing or housing 8 provided with rollers 9 at either end upon opposite sides upon which lthe mold 1'3 may revolve. The housing is carried at its ends upon flanged Wheels 10 which rest upon track rails 11 extending along 'opposite sides of the housing." I `The housing 8y may be formed 1n two longitudinal divided halves bolted together. The right-hand end is provided with` an end ring member 8l spaced away to provide an annular space to receive the gear ring 4, and secured in any suitable manner to the bodyJ 'of the housing as by *a number of straps Sb-.bolted to ermit the ring member to be. readily de taiched when a mold is Vto be inserted or re-f rmoved. The joints betweenthe stationary housing and the rotatable mold and the rotary sleeve -5 maybe closed by means of split piston rings 5a.

The mold is rotated by means ofasuitable motor 1 mounted on the housing and provided with a pinion 2, in mesh with a gear 3, which drivesgtlie gear ring 4, splined to the /rotary sleeve 5 which revolves in bearings 'mannen The housing "may bemoyed longimotoris rotating the mold, by means of the "hydraulic cylinder 6, having its piston rod l 7 secured to the block 7 a carried by the housis inserted in the mold for rolling the latter ing.

We have devised a special rolling tool which is employed for closing the cracks in the mold and this tool consists of a sleeve through which extends a shaft 16. To one end of the sleeve 15 is pinned or otherwise secured a sleeve 17 of suiicient diameter to surround the shaft 16 in spaced relationand within this sleeve adjacent its center, is secured a, collar 18 through which the shaft passes. Telescopically mounted in the open end of the sleeve 17 is a short sleeve 19 through which the threaded end 20 ofthe A shaft 16 passes. On this threaded endV is screwed an adjusting nut 21 and between said nut and the sleeve 19 is a washer 22. Within the sleeve-17 between the collar 18 and sleeve .19 is a coiled compression spring 23 and a sim- 1lar spring 24 is arranged on the opposite side of said collar and bears against a collar 25 pinned to the shaft 16. This arrangement permits adjustment of the shaftv16 in the sleeve 15, while, at the same time, permitting the shaft to move in either direction against the action of said springs. i

On the opposite or forward end of the sleeve 15 is pinned a head 26 which is splined to the shaft 16 by a key 27 The forward end of the shaft 16 is reduced and on this forward end is fixed what may be termed a movable head 28, the head 26 being a fixed head in comparison. 'The head 28 is held on the shaft by a nut 29 and washer 30. The adjacent ends of these heads are frustoconical in form and on these frusto-conical ends rest the corresponding ends of rollers 31 having l journals 32 mounted in the radial slots 33 of a roller cage 34. End plates 35 are held to the cage by bolts 36. The rollers can thus move in and out radially and project beyond the periphery of the cage. This rolling head and the rollers 31 are adjusted to bear against the interior of the mold by proper manipulation of the nut 21, revolution in one direction moving the head 28 toward the head 26 and causing projection of the rollers and revolution'of the nut in the other direction aly:sa

veo

lowing the heads to separate and the rollers to move inwardly. c

Jn Figure 3 there is diagrammatically disclosed the condition of a mold 13 under checking and it will be noted that the interior of the mold is full of radial cracks, the edges of which have sprung upwardly under the influence of the stresses set up by alternate heating and cooling. If the roller head be revolved through such a mold in proper ad- ]ustment the pressure exerted by the rollers will-,force these edges back to the normal surface and, due to the decrease in the curvain Fig. 3 and are more like those illustrated in Fig. 5, so that they may be closed and the inner surface may be made smooth as indicated in Fig. 7.

If there be any variations in the diameter of the Inold the springs 23 and 24 will permit automatic adjust-ment of the rollers to compensate for such variations.

l/Vhile the mold has been here shown as rotating during the operation it is obvious that the mold may be stationary while thek rollers are revolved, with the same result.

' We claim v 1. Thel method of repairing interiorly cracked metallic molds which consists in applying pressure to the mold at the edges of the cracks Isuliicient to force the edges of each crack together.

2. Themethodofrepairingtheinteriorsurfaces of molds having cracks therein wherein the edges of the cracked portions are curled up from the normal surface at the sides of the cracks which consists in exerting sulficient pressure on the said interior surface to force the curled up Aportions into normal surface positions and thereby bringing the sides of the cracks together at said surface.

3. The method of repairing a tubular metallic mold having Surface cracks extending into its internal surface Which consists in subjecting the cracked surface to a rolling operation to thereby bring the sides of the cracks together at said surface.

4. In a device for rolling the checked surface of internally checked tubular metallic molds, a sleeve, a shaft extending through said sleeve, a lixed head on one end of the sleeve, a movable head carried by the correspending end of the shaft, said heads having opposed frusto-conical ends, rollers having frusto-conical ends resting on the frustoconical ends of the heads, a roller cage supporting said rollers on said heads, and rcsiliently yieldabl'e means to impart longitudinal movement of the shaft relative to the sleeve in either direction to thereby automatically adjust the rollers to compensate for variations in the interior wall of the mold.

5. In a device for rolling the checked surface of internally checked tubular metallic molds, a sleeve, a shaft extending through said sleeve, a fixed head on one end of the sleeve, a movable head carried by the corresponding end of the shaft, said heads having opposed frusto-conica-l ends, rollers having frusto-conical ends resting on the frusto-conical ends ofthe heads, a roller cage supporting said rollers on said heads, a second sleeve carried by the first sleeve and spaced shaft in spaced relation to the first collar 10 concentrically from the shaft, a collar fixed and on the side opposite the spring, and a within the second sleeve and surrounding second coiled compression sprlng between the shaft, a third sleeve telescopically mountsaid collars.

ed in the end of the second sleeve, an ad- In testimony whereof we ax our signajusting nut screwed on said shaft to force tures.

the third sleeve inwardly of the second sleeve, A

a coiled compression spring between the col-1 WILLIAM M. MARTIN.

lar and third sleeve, a collar fixed to the CHAS. N. CHURCH. 

